Ceramic structures such as honeycomb structures have been used in filters for capturing particulates, particularly diesel particulates in exhaust gases of internal combustion engines, boilers and the like.
In general, as shown in FIGS. 5(a) and (b), the ceramic structure used for this purpose, for example, the honeycomb structure has a structure including a large number of through channels 3 divided by partition walls 2 and extending in an X-axis direction, and sealed portions in which adjacent through channels 3 are sealed in end portions on opposite sides in such a manner that end surfaces have checkered patterns. In the honeycomb structure having this structure, fluid to be treated flows in the through channel 3 which does not have the sealed portion in one end surface 42, that is, the through channel 3 which has the sealed portion in the other end surface 44, and is discharged from the adjacent through channel 3 through a porous partition wall 2, that is, the through channel 3 which has the sealed portion in one end surface 42 and which does not have the sealed portion in the other end surface 44. In this case, the partition walls 2 function as filters. For example, soot and the like discharged from a diesel engine are captured by the partition walls and deposited on the partition walls.
However, kinks are sometimes generated in sealed portions 10 as shown in FIG. 6, and there has been a problem that a filter function is deteriorated by the generation of kinks 20. Fluctuations are also easily generated in depths x of the sealed portions 10, and the filter function has also been adversely affected.